1. Field of the Invention
The invention is related to inspection tools for measuring the wall thickness of underground storage tanks, especially fiberglass-reinforced plastic (FRP) storage tanks, and particularly fuel storage tanks.
2. Description of the Prior Art
Zero Interface Probes (ZIP) have been in use for many years, however, previous use has been limited solely to hand-held instruments. There are no known means for the use of such probes where access to humans is denied, i.e., where the probes cannot be hand-held.